Microcrystalline wax coating compositions



United ,States Bateiit 3,004,854 MICROCRYSTALLINE WAX COATING COMPOSITIONS Y Stephen H. Alexander, ElDorado, Art, and Arnold I. V Hoiherg, Montville, l l.l.; said Alexander assignor to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Filed Aug. 25, 1958, Ser. No. 757,116 Claims. (Cl. 106-14) This invention relates to microcrystalline wax compositions having exceptional utility as protective coatings, particularly for metallic surfaces.

Coating compositions, wherein the film-former is principally a microcrystalline wax, have been used with some degree of success. Such compositions would enjoy a much more wide spread field of utility if means were found to increase the rust or corrosion-preventative characteristics of these compositions, particularly when applied to metal surfaces. Such is the broad object of this invention. Other objects of this invention will become apparent from the description which follows:

It has now been discovered that compositions comprising a microcrystalline wax and a minor amount of finely divided aluminum, preferably from about 1% to about 15% by weight of total composition of finely divided aluminum, are excellent protective coatings and metallic surfaces coated therewith are exceedingly resistant to deterioration due to rusting. In many applications it is desira'ole to employ a softening agent to improve or enhance the flow characteristics of microcrystalline wax. Asphalt fluxes are particularly useful in this regard. Preferred compositions of this invention comprises a major amount of microcrystalline wax, a minor amount of an asphalt flux as a softening agent and from about 1% to about 15% by weight of total composition of finely divided aluminum powder. The following examples of such compositions illustrate this invention:

Example I To a mixture of microcrystalline wax and an asphalt flux, was added varying quantities of aluminum powder. The microcrystalline wax had a dropping point of 175 F. (ASTM test D-127 and a penetration of 62 mm./1O at 77 F. (ASTM test D-5-52). The fiux was a smackover flux of 32 sec. float at 122 F. (ASTM test D-139- 49.) The aluminum powder was a fineness such that a maximum of 1% by weight was retained on a standard 325 mesh screen. The aluminum powder was added as a paste composed of aluminum powder dispersed in 35% by weight of mineral spirits. Metal panels were then coated with the compositions by dipping at 170180 F. The coated panels were then exposed to accelerated weathering (ASTM test D-529-39T, cycle A, except "without cold exposure). The results obtained were as Patented Oct. 17, 1951 A comparison of samples 2, 3 and 4 with sample 1' clearly indicates the advantages to be gained through the practice of invention.

Example 11 Ten parts by weight of aluminum particles of a fine-z ness such that a maximum of 1% by weight is retainedon a standard 325 mesh screen is incorporated by mixing. into 100 parts by weight of microcrystalline wax having a dropping point of 175 F. (ASTM test D-l27) and a penetration of 62 mm./l0 at 77 F. (ASTM test D-S- 52). Metal panels are dip coated with this composition at a temperature of l-180 F. The coated panels exhibit excellent resistance to deterioration due to rusting on exposure to outdoor weathering.

Any microcrystalline wax can be used in the preparation of the novel compositions of this invention. The aluminum added to the wax to prepare the coating compositions of this invention should be finely divided and preferably of a particle size smaller than about 200 mesh, that is, substantially 100% through a standard No. 200 mesh screen. The aluminum is used in an amount varying from about 1% to about 15% by Weight of total composition. The aluminum can be added as such or as a paste with an inert solvent as shown in the example. The aluminum can be mixed with the microcrystalline wax by any convenient method that will produce a homogeneous dispersion. Simple mixing of the components is usually sufiicient.

The asphalt flux used in the preferred compositions of this invention serves as a softening agent for the microcrystalline wax, imparting to it the desired flow properties. While any asphalt flux can be used, those having a float of less than about 200 sec. at 122 F. (ASTM test D-139-49) are preferred. The quantity of flux used is dependent upon the fiow properties desired in the finished composition. Generally only minor amounts of asphalt flux are required and from about 5% to about 40% by weight of total composition of asphalt flux is particularly useful.

The coating compositions of this invention can be used as such or contain added fillers such as asbestos fibers, vermiculite, clays, etc. if desired. These coating compositions can be applied to any surface by any convenient method such as by pouring, dipping, painting, spraying, etc. The compositions of this invention are particularly useful as protective coatings for metals.

What is claimed is:

l. A protective coating composition consisting essentially of a mixture of a major amount of microcrystalline wax, a minor amount of an asphalt flux and a minor amount of finely divided aluminum.

2. A protective coating composition containing essentially of a mixture of a major amount of microcryst-alline wax, a minor amount of an asphalt flux and from about 1% to about 15% by weight of total composition of finely follows: divided aluminum.

Sample No 1 2 3 4 Composition:

Micrcwsx, percent by w 65.0- 62.1. no 2 55,0 Asphalt flux, percent by w 35.0- 34 1 32 3 30.0 Aluminum paste, percent by wt.. 0.0. 3.8. 7.5 15.0 Cone penetration of blend at 77 F. 7 68 66 (ASTM test D-217-52T). Film Thickness, mils 1.7 1.6- l 6 1.5. A celerated weathering:

L Light hours 309..-" 309 309 300.

Film appearance Smooth Continuous- Smooth Continuous- Smooth Continuous- Smooth Continuous. Panel appearance alter film removal.- area very light 50% area very light Traces of rust N o rust.

rus rus 3. A protective coating composition as described in claim 2 wherein the asphalt flux has a float value of less than about 200 sec. at 122 F.

4. A protective coating composition as described in claim 3 wherein the aluminum is of a particle size such that substantially 1;00%iof the particles pass-through a standard 200 mesh scr'eenr; 7 V ,7 V

5. A method of protecting metallic smfaces'consistin-g essentially of coating said metallic surfaces with a protective coating composition consisting essentially of a mixture of a major amount of microcrystalline' wax, a minor amount of asphalt flux an'd a minor amount of finely divided aluminum.

References Cited in the file of this patent UNITED'STATES PATENTS Hickok Nov. 7, 1933 Holt ...:i. July 7, 1935 Strauss Dec. 26, 1939 4 O Neil Sept. 9, 1952 Stosselj,. l Nov. 13, 1956 Vierk' Mar. 12, 1957 

1. A PROTECTIVE COATING COMPOSITION CONSISTING ESSENTIALLY OF A MIXTURE OF A MAJOR AMOUNT OF MICROCRYSTALLINE WAX, A MINOR AMOUNT OF AN ASPHALT FLUX AND A MINOR AMOUNT OF FINELY DIVIDED ALUMINUM. 